Merging polyhedral shapes with scattered features

1. initial embeddings of the polyhedra on unit spheres are computed, 2. the embeddings are deformed so that user-defined features (vertices) coincide on the spheres, and 3. an overlay of the subdivisions is computed and the aligned vertices are fused in the merged model.     

Network capacity analysis for latent attractor computation

Attractor networks have been one of the most successful paradigms in neural computation, and have been used as models of computation in the nervous system. Recently, we proposed a paradigm called 'latent attractors' where attractors embedded in a recurrent network via Hebbian learning are used to channel network response to external input rather than becoming manifest themselves. This allows the network to generate context-sensitive internal codes in complex situations. Latent attractors are particularly helpful in explaining computations within the hippocampus--a brain region of fundamental significance for memory and spatial learning. Latent attractor networks are a special case of associative memory networks. The model studied here consists of a two-layer recurrent network with attractors stored in the recurrent connections using a clipped Hebbian learning rule. The firing in both layers is competitive--K winners take all firing. The number of neurons allowed to fire, K, is smaller than the size of the active set of the stored attractors. The performance of latent attractor networks depends on the number of such attractors that a network can sustain. In this paper, we use signal-to-noise methods developed for standard associative memory networks to do a theoretical and computational analysis of the capacity and dynamics of latent attractor networks. This is an important first step in making latent attractors a viable tool in the repertoire of neural computation. The method developed here leads to numerical estimates of capacity limits and dynamics of latent attractor networks. The technique represents a general approach to analyse standard associative memory networks with competitive firing. The theoretical analysis is based on estimates of the dendritic sum distributions using Gaussian approximation. Because of the competitive firing property, the capacity results are estimated only numerically by iteratively computing the probability of erroneous firings. The analysis contains two cases: the simple case analysis which accounts for the correlations between weights due to shared patterns and the detailed case analysis which includes also the temporal correlations between the network's present and previous state. The latter case predicts better the dynamics of the network state for non-zero initial spurious firing. The theoretical analysis also shows the influence of the main parameters of the model on the storage capacity.     

Efficient Computation of Smoothed Exponential Maps

Many applications in geometry processing require the computation of local parameterizations on a surface mesh at interactive rates. A popular approach is to compute local exponential maps, i.e. parameterizations that preserve distance and angle to the origin of the map. We extend the computation of geodesic distance by heat diffusion to also determine angular information for the geodesic curves. This approach has two important benefits compared to fast approximate as well as exact forward tracing of the distance function: First, it allows generating smoother maps, avoiding discontinuities. Second, exploiting the factorization of the global Laplace–Beltrami operator of the mesh and using recent localized solution techniques, the computation is more efficient even compared to fast approximate solutions based on Dijkstra's algorithm.     

Single-phase inverter with Z.V.S. capacitors connected on the D.C. side and the load in parallel with the resonance inductance

Contents The paper presents one new version of single-phase inverters having the capacitors for the Z.V.S. connected in the D.C. side and the load in parallel with the resonance inductance. The output frequency of this inverter can be changed in certain ranges, from a maximum frequencyf _max to a minimum frequencyf _min, without imposing a constant load impedanceL–R. The power losses due to the commutation process of the switching devices comprising the inverter are drastically reduced and the resonant pulses have small dv/dt-values, allowing a high electromagnetic compatibility of the proposed inverter.

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Einphasenwechselrichter mit Kondensatoren im Gleichstromzwischenkreis zum Kommutieren auf die Nullspannung und Parallelbelastung mit Resonanzinduktanz

Übersicht Die Arbeit stellt eine neue Variante von Einphasenwechselrichtern vor, die Kondensatoren im Gleichstromzwischenkreis zum Kommutieren auf die Nullspannung und Parallelbelastung mit Resonanzinduktanz haben. Die Ausgangsfrequenz dieser Wechselrichter kann in gewissen Grenzen variiert werden, zwischen der maximalen Frequenzf _max und der minimalen Frequenzf _min, ohne daß es notwending ist, die LastimpedanzL–R konstant zu halten. Die Leistungsverluste in den Kommutierungsprozessen der in den Kondensatoren befindlichen Halbleiterelemente werden drastisch reduziert, und die Schwingungspulse haben Anstiegeschwindigkeiten dv/dt von ebenfalls reduzierten Werten, was zu einer erhöhten elektromagnetischen Kompatibilität der vorgeschlagenen Wechselrichter führt.

     

Evaluation of Putative Allelochemicals in Rice Root Exudates for Their Role in the Suppression of Arrowhead Root Growth

In previous studies, 15 putative allelopathic compounds detected in rice root exudates were quantified by GC/MS/MS. In this study, multiple regression analysis on these compounds determined that five selected phenolics, namely caffeic, p-hydroxybenzoic, vanillic, syringic, and p-coumaric acids, from rice exudates were best correlated with the observed allelopathic effect on arrowhead (Sagittaria montevidensis) root growth. Despite this positive association, determination of the phenolic acid dose-response curve established that the amount quantified in the exudates was much lower than the required threshold concentration for arrowhead inhibition. A similar dose-response curve resulted from a combination of all 15 quantified compounds. Significant differences between the amounts of trans-ferulic acid, abietic acid, and an indole also existed between allelopathic and non-allelopathic rice cultivars. The potential roles of these three compounds in rice allelopathy were examined by chemoassay. Overall, neither the addition of trans-ferulic acid nor 5-hydroxyindole-3-acetic acid to the phenolic mix significantly contributed to phytotoxicity, although at higher concentrations, trans-ferulic acid appeared to act antagonistically to the phytotoxic effects of the phenolic mix. The addition of abietic acid also decreased the inhibitory effect of the phenolic mix. These studies indicate that the compounds quantified are not directly responsible for the observed allelopathic response. It is possible that the amount of phenolic acids may be indirectly related to the chemicals finally responsible for the observed allelopathic effect.     

Influence of NaCl,Na2SO4 and O2 on power generation from microbial fuel cells with non-catalyzed carbon electrodes and natural inocula

Microbial fuel cells (MFCs) are facing several technological challenges before they can be considered as reliable energy sources. Although several feasible inocula, materials and catalysts have been employed to produce energy, the design of a MFC should be done under realistic conditions: abundant and economic feedstock. In this study, two different MFC designs (parallel plate and tank reactors) are tested with non-catalyzed carbon electrodes and natural inocula. In both approaches cathodic oxygen reduction is performed on two different non-catalyzed carbon materials: carbon fabric and reticulate vitreous carbon. This study shows that power and current densities can be boosted by systematically decreasing the catholyte resistance (by additions of NaCl or Na₂SO₄) and dissolved oxygen concentration. In the parallel plate cell configuration, a mixed culture coming from sludge wastewater was used and power outputs up to 73 mW m^?2 (2867 mW m^?3) coupled to 187 mA m^?2 (anode surface area), were achieved. In the Sediment MFC cell configuration, lagoon sediment was used as both organic source of energy and natural supply of bacteria. Under this approach, the concentration of the organic matter is limited but it is demonstrated that bacteria can be adapted to degrade acetate. Power outputs up to 3.9 mW m^?2 normalized to the anodic electrode footprint area, coupled to 13 mA m^?2 were achieved.     

Combining informetrics and trend analysis to understand past and current directions in electronic design automation

Scientometrics - There has been increasing interest in the study of research communities with the goal of optimizing their outcomes and impact. While current methods can predict future trends, they...     

Thinking Small: Small Molecules as Potential Synergistic Adjuncts to Checkpoint Inhibition in Melanoma

Metastatic melanoma remains the deadliest form of skin cancer. Immune checkpoint inhibition (ICI) immunotherapy has defined a new age in melanoma treatment, but responses remain inconsistent and some patients develop treatment resistance. The myriad of newly developed small molecular (SM) inhibitors of specific effector targets now affords a plethora of opportunities to increase therapeutic responses, even in resistant melanoma. In this review, we will discuss the multitude of SM classes currently under investigation, current and prospective clinical combinations of ICI and SM therapies, and their potential for synergism in melanoma eradication based on established mechanisms of immunotherapy resistance.     

Optimized combined harmonic filtering system

This paper presents a thorough analysis of the operation for the combined filtering system consisting of a passive filter with diodes connected in parallel with the capacitors and a low-power inverter. The diodes limit the voltage across the capacitors and the inverter starts to work when disturbances occur in the three-phase network, sending back to the network the excess energy taken by all the capacitors from the network during these disturbances. The proposed combined filtering system has reduced size and cost as well as high efficiency. Laboratory experiments and simulation results proving the effectiveness of the solution are also presented     

Assessment of computer generated vision charts

Introduction

New opportunities for vision assessment in the consulting room are given with the application of computers. This study cross-validated high and low contrast visual acuity (VA) data measured using traditional paper charts and new computerised technology applying the chart design of Bailey and Lovie. In addition, subjects’ contrast sensitivity (CS) was tested with a computerised CS test, and the effect of memorisation was determined using a traditional chart.

Methods

The habitual vision of 40 adult subjects (mean age 36) was measured with both low and high contrast methods as well as with the CS test. For testing the memorisation effect, 17 (mean age 33.1) of the 40 subjects were tested with the traditional high contrast chart five times in 1 day, at least 1 h apart. The fifth test and a control test, conducted 4 weeks later, were accomplished under low illumination. All tests were conducted three times, both binocular and monocular right and left. Also, testing times were recorded.

Results

Both methods were very repeatable in terms of high and low contrast VA. The mean VA of both methods did not differ by more than one letter. The testing times of the paper charts were not more than 2 s faster than with the new method. A memorisation effect could not be demonstrated after five repeat visits within 1 day. The computerised CS test was repeatable but showed only poor correlation with the low contrast VA test.

Conclusion

This investigation showed that results from high and low contrast paper charts are directly comparable to computerised vision testing in terms of repeatability, accuracy and testing time. Given the additional advantages of better contrast control, more flexibility and test options, together with the general acceptance and positive feedback from patients, paper charts can be replaced by computer monitors without any adverse implications.